ENGLISH
Version 041027
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2. DESCRIPTION OF PROCESS
The treatment section is carried out in two stages:
- Pre-treatment.
- Desalination with Reverse Osmosis.
PRE-TREATMENT:
This stage of the process is designed to remove larger varieties of contaminants that would
otherwise interfere with the short and long term performance of the reverse osmosis
membranes.
Feed water enters the unit through a mesh filter (not shown on the diagram). The mesh
filter absorbs large particles that would plug feed pipes or cause damage to the pump. This
filter will not be included the delivery from ENWA AB. Recommended mesh size is 0,5-
2,5 mm. The mesh filter supplied has to be manufactured from a non-corrosive material.
The feed water will then continue to the feed water pump which increases the feed water
pressure to 1,5 - 2,5 bar, but can under some circumstances be higher or lower.
A feed water valve (HV-2010) controls the feed water supply from the mesh filter and a
check valve (CV-2010) will ensure that flushing water not will flow backwards through
the feed water pump. The feed water will then continue to the feed water filter (F-2010)
and you can see the pressure on the pressure indicator (PI-2011).
The flush water filter (F-2020) contains an activated carbon cartridge, the purpose of the
filter is to de-chlorinate the flushing water from the storage. These filters will absorb
suspended matter larger than 10 micron size.
DESALINATION WITH REVERSE OSMOSIS
The feed water will then continue to the high-pressure pump (HPP-2010) that will
increase the feed water pressure to normal operation pressure (See general operation
conditions). After the high pressure pump the feed water continues to the R.O-module
(RO-2030, eventually -31, -32, -33, -34) that desalinates the water.
Two streams will pass out from the module; one is product and the other one is brine (salt
concentrate). The brine will continue to the pressure regulating valve (PCV-2050) which
by opening or closing will decrease respectively increase the operation pressure. Actual
operational pressure is shown on the pressure indicator (PI-2050) upstream the R.O-
module. The brine will then continue to sea as waste.
The product from the R.O-module will pass through a conductivity-cell that measures the
conductivity in the product water. The conductivity meter (1u400) will influence the
solenoid valve (ROV-2060) that divides the product water to tank or waste. If the
